1. Field of the Invention
The present invention relates to an object-throwing video game system, and more particularly to an object-throwing video game system which employs a cassette-type recording medium for storing video game data, such as an optical disk, a magnetic disk, a magnetooptical disk, or a semiconductor memory, a method of displaying a guide image in an object-throwing video game which can be played on such an object-throwing video game system, and a recording medium for storing video game data of an object-throwing video game which can be played on such an object-throwing video game system.
2. Description of the Prior Art
Various video game systems which have been proposed in the art include video game systems comprising a combination of a video game machine designed for home use and a television monitor, video game systems designed as video game machines for business use, and video game systems comprising a combination of a personal computer or work station, a display unit, and an audio output unit. These video game systems commonly comprise a controller which can manually be operated by a game player, a recording medium which stores game data including game program data and graphic image data and audio data, a central processing unit (CPU) for performing a control process based on the game program data to generate graphic images and sounds from the graphic image data and audio data, a graphic processor for processing the graphic image data, an audio processor for processing the audio data, a cathode-ray tube (CRT) for displaying graphic images, and a speaker for outputting sounds. The recording medium may typically be a CD-ROM, a semiconductor memory, a cassette with a built-in semiconductor memory, or the like.
Video games are available in an increasing number of different types and become more and more complex and diverse in nature. One type of video sports games which has been proposed recently allows the game player to move a contestant displayed on the display screen of a television monitor with a controller to play a virtual sports match in a game space displayed on the display screen.
Sports contests include group competition contests such as soccer games and baseball games and individual competition contests. The individual competition contests are roughly classified into running contests, swimming contests, contests in which contestants fly, contests in which contestants lift objects, contests in which contestants fight with each other, contests in which contestants hit targets with objects, and object-throwing contests in which contestants throw objects. The object-throwing contests include shot put, hammer throw, discus throw, javelin throw, etc. If any of these object-throwing contests is realized as a video game, then it will most likely be played by the game player as follows: When the game player operates a controller of the video game system, the control unit of the video game system visually moves a contestant displayed in a game space on the display screen of a display monitor based on a command entered from the controller thereby to perform in the contest.
In the shot put, the contestant throws the ball after he has turned about 180.degree.. In the hammer throw and discus throw, the contestant hurls the hammer or discus after having turned a plurality of times in a throwing circle. In order to realize such an object-throwing contest as a video game, it is necessary at least to establish the throwing energy of the contestant with a controller operated by the game player, display the image of the contestant as he turns 180.degree. or several times in a game space on the display screen, display the image of the contestant as he throws the object in the game space with the controller while the contestant is turning 180.degree. or several times, and display the object as it flies in the game space based on the established throwing energy, a throwing direction, and a throwing angle, so that the contest performed in the game space will look like real contests as much as possible.
If the direction in which the object flies in the game space is determined based on only the posture of the contestant displayed in the game space, however, the game player finds it difficult to decide the exact time for the contestant in the game space to hurl the object. This is because the game player has to decide the exact time for the contestant in the game space to hurl the object based on only contestant images that are successively displayed on the display screen.
In a hammer throw video game, a predictive vector represented by the image of arms of the contestant in the game space differs from a predictive vector represented by the image of the hammer that is being turned by the contestant. When a moving image of the contestant who is throwing the hammer is generated using a motion capture process, inertia is visually expressed in the same manner as actual inertia. Therefore, the image of the hammer is displayed behind the image of the arms of the contestant which is turning with respect to the direction in which the contestant is turning. The game player thus has difficulty in deciding the time at which the contestant in the game space should release the hammer.
In each of object-throwing contests such as hammer throw and discus throw in which the object is hurled after having turned a plurality of times, there is a principal count of turns which the object should make before it is hurled. In video games of those object-throwing contests, it is necessary to declare a throw failure if the object is not hurled when the count of its turns reaches the principal count of turns. Declaring a throw failure in such a case makes the object-throwing video game interesting and fun to play. However, since the game player needs to count how many times the object should turn before it is hurled while seeing the image of the object turn in the game space, the game player tends to induce a count error and disturb their concentration on the video game as it proceeds, possibly adversely affecting the results of the video game.